Bug 1338260. Add Fennec-only UA override for directv.com. r=mconnor
They use an older version of Sencha Touch (v2.1.0) which is known
to not be compatibile with Firefox. However, pretending to be Chrome
fixes the issue of not being able to scroll and various paint bugs.
MozReview-Commit-ID: K35ll42Xxlt

Bug 1246846 (part 2) - Avoid nsTHashtable::RawRemoveEntry() in nsPermissionManager. r=mconnor.
This assumes that it's safe to possibly shrink the table after the removal,
i.e. there are no surprising subtleties with how this table is managed.